It really depends on the niche that you're targeting.

For example, I know of an online store that sells wine but they sold wines that came from a fairly specific region - when they started marketing their site, they sent free bottles of wine to various wine blogs and reviewers, with a very simple "With Compliments" card.

They didn't ask to be reviewed, but ended up being reviewed favourably anyway, and garnered a decent amount of traffic.

Anyway, the point of the story is that if you are targeting people who are passionate about a specific area of interest, you can often get away with giving something that has more than a monetary value as long as you are being creative.

At least thats my opinion.